const QR = require('./qrcode.js')
const GD = require('./gradient.js')
export default class Painter {
  constructor(ctx, data) {
    this.ctx = ctx
    this.data = data
    this.globalWidth = {}
    this.globalHeight = {}
  }
  paint(callback) {
    this.style = {
      width: this.data.width.toPx(),
      height: this.data.height.toPx()
    }
    this._background()
    if (this.data.views && this.data.views.length > 0) {
      for (const view of this.data.views) {
        this._drawAbsolute(view)
      }
    }

    callback()
  }
  _background() {
    this.ctx.save()
    const { width, height } = this.style
    const bg = this.data.background
    this.ctx.translate(width / 2, height / 2)
    this._doClip(this.data.borderRadius, width, height)
    if (!bg) {
      // 如果未设置背景，则默认使用白色
      this.ctx.fillStyle = '#fff'
      this.ctx.fillRect(-(width / 2), -(height / 2), width, height)
    } else if (bg.src) {
      // 背景填充图片
      this.ctx.drawImage(bg, -(width / 2), -(height / 2), width, height)
    } else if (bg.startsWith('#') || bg.startsWith('rgba') || bg.toLowerCase() === 'transparent') {
      // 背景填充颜色
      this.ctx.fillStyle = bg
      this.ctx.fillRect(-(width / 2), -(height / 2), width, height)
    } else if (GD.api.isGradient(bg)) {
      GD.api.doGradient(bg, width, height, this.ctx)
      this.ctx.fillRect(-(width / 2), -(height / 2), width, height)
    }
    this.ctx.restore()
  }
  _drawAbsolute(view) {
    // 证明 css 为数组形式，需要合并
    if (view.css && view.css.length) {
      /* eslint-disable no-param-reassign */
      view.css = Object.assign(...view.css)
    }
    switch (view.type) {
      case 'image':
        this._drawAbsImage(view)
        break
      case 'text':
        this._fillAbsText(view)
        break
      case 'rect':
        this._drawAbsRect(view)
        break
      case 'qrcode':
        this._drawQRCode(view)
        break
      default:
        break
    }
  }

  /**
   * 根据 borderRadius 进行裁减
   */
  _doClip(borderRadius, width, height) {
    if (borderRadius && width && height) {
      const r = Math.min(borderRadius.toPx(), width / 2, height / 2)
      // 防止在某些机型上周边有黑框现象，此处如果直接设置 fillStyle 为透明，在 Android 机型上会导致被裁减的图片也变为透明， iOS 和 IDE 上不会
      // globalAlpha 在 1.9.90 起支持，低版本下无效，但把 fillStyle 设为了 white，相对默认的 black 要好点
      this.ctx.globalAlpha = 0
      this.ctx.fillStyle = 'white'
      this.ctx.beginPath()
      this.ctx.arc(-width / 2 + r, -height / 2 + r, r, 1 * Math.PI, 1.5 * Math.PI)
      this.ctx.lineTo(width / 2 - r, -height / 2)
      this.ctx.arc(width / 2 - r, -height / 2 + r, r, 1.5 * Math.PI, 2 * Math.PI)
      this.ctx.lineTo(width / 2, height / 2 - r)
      this.ctx.arc(width / 2 - r, height / 2 - r, r, 0, 0.5 * Math.PI)
      this.ctx.lineTo(-width / 2 + r, height / 2)
      this.ctx.arc(-width / 2 + r, height / 2 - r, r, 0.5 * Math.PI, 1 * Math.PI)
      this.ctx.closePath()
      this.ctx.fill()
      this.ctx.clip()
      this.ctx.globalAlpha = 1
    }
  }

  /**
   * 画边框
   */
  _doBorder(view, width, height) {
    if (!view.css) {
      return
    }
    const { borderRadius, borderWidth, borderColor } = view.css
    if (!borderWidth) {
      return
    }
    this.ctx.save()
    this._preProcess(view, true)
    let r
    if (borderRadius) {
      r = Math.min(borderRadius.toPx(), width / 2, height / 2)
    } else {
      r = 0
    }
    const lineWidth = borderWidth.toPx()
    this.ctx.lineWidth = lineWidth
    this.ctx.strokeStyle = borderColor || 'black'
    this.ctx.beginPath()
    this.ctx.arc(-width / 2 + r, -height / 2 + r, r + lineWidth / 2, 1 * Math.PI, 1.5 * Math.PI)
    this.ctx.lineTo(width / 2 - r, -height / 2 - lineWidth / 2)
    this.ctx.arc(width / 2 - r, -height / 2 + r, r + lineWidth / 2, 1.5 * Math.PI, 2 * Math.PI)
    this.ctx.lineTo(width / 2 + lineWidth / 2, height / 2 - r)
    this.ctx.arc(width / 2 - r, height / 2 - r, r + lineWidth / 2, 0, 0.5 * Math.PI)
    this.ctx.lineTo(-width / 2 + r, height / 2 + lineWidth / 2)
    this.ctx.arc(-width / 2 + r, height / 2 - r, r + lineWidth / 2, 0.5 * Math.PI, 1 * Math.PI)
    this.ctx.closePath()
    this.ctx.stroke()
    this.ctx.restore()
  }

  _preProcess(view, notClip) {
    let width = 0
    let height
    let extra
    switch (view.type) {
      case 'text': {
        const textArray = view.text.split('\n')
        // 处理多个连续的'\n'
        for (let i = 0; i < textArray.length; ++i) {
          if (textArray[i] === '') {
            textArray[i] = ' '
          }
        }
        const fontWeight = view.css.fontWeight === 'bold' ? 'bold' : 'normal'
        view.css.fontSize = view.css.fontSize ? view.css.fontSize : '20px'

        this.ctx.font = `normal ${fontWeight} ${view.css.fontSize.toPx()}px ${view.css.fontFamily ? view.css.fontFamily : 'sans-serif'}`
        // this.ctx.setFontSize(view.css.fontSize.toPx());
        // 计算行数
        let lines = 0
        const linesArray = []
        for (let i = 0; i < textArray.length; ++i) {
          const textLength = this.ctx.measureText(textArray[i]).width
          const partWidth = view.css.width ? view.css.width.toPx() : textLength
          const calLines = Math.ceil(textLength / partWidth)
          width = partWidth > width ? partWidth : width
          lines += calLines
          linesArray[i] = calLines
        }
        lines = view.css.maxLines < lines ? view.css.maxLines : lines
        const lineHeight = view.css.lineHeight ? view.css.lineHeight.toPx() : view.css.fontSize.toPx()
        height = lineHeight * lines
        extra = {
          lines: lines,
          lineHeight: lineHeight,
          textArray: textArray,
          linesArray: linesArray
        }
        break
      }
      case 'image': {
        // 有css却未设置width或height，则默认为auto
        if (view.css) {
          if (!view.css.width) {
            view.css.width = 'auto'
          }
          if (!view.css.height) {
            view.css.height = 'auto'
          }
        }
        if (!view.css || (view.css.width === 'auto' && view.css.height === 'auto')) {
          width = Math.round(view.sWidth)
          height = Math.round(view.sHeight)
        } else if (view.css.width === 'auto') {
          height = view.css.height.toPx()
          width = (view.sWidth / view.sHeight) * height
        } else if (view.css.height === 'auto') {
          width = view.css.width.toPx()
          height = (view.sHeight / view.sWidth) * width
        } else {
          width = view.css.width.toPx()
          height = view.css.height.toPx()
        }
        break
      }
      default:
        if (!(view.css.width && view.css.height)) {
          console.error('You should set width and height')
          return
        }
        width = view.css.width.toPx()
        height = view.css.height.toPx()
        break
    }
    let x
    if (view.css && view.css.right) {
      if (typeof view.css.right === 'string') {
        x = this.style.width - view.css.right.toPx(true)
      } else {
        // 可以用数组方式，把文字长度计算进去
        // [right, 文字id, 乘数（默认 1）]
        const rights = view.css.right
        x = this.style.width - rights[0].toPx(true) - this.globalWidth[rights[1]] * (rights[2] || 1)
      }
    } else if (view.css && view.css.left) {
      if (typeof view.css.left === 'string') {
        x = view.css.left.toPx(true)
      } else {
        const lefts = view.css.left
        x = lefts[0].toPx(true) + this.globalWidth[lefts[1]] * (lefts[2] || 1)
      }
    } else {
      x = 0
    }
    //const y = view.css && view.css.bottom ? this.style.height - height - view.css.bottom.toPx(true) : (view.css && view.css.top ? view.css.top.toPx(true) : 0);
    let y
    if (view.css && view.css.bottom) {
      y = this.style.height - height - view.css.bottom.toPx(true)
    } else {
      if (view.css && view.css.top) {
        if (typeof view.css.top === 'string') {
          y = view.css.top.toPx(true)
        } else {
          const tops = view.css.top
          y = tops[0].toPx(true) + this.globalHeight[tops[1]] * (tops[2] || 1)
        }
      } else {
        y = 0
      }
    }

    const angle = view.css && view.css.rotate ? this._getAngle(view.css.rotate) : 0
    // 当设置了 right 时，默认 align 用 right，反之用 left
    const align = view.css && view.css.align ? view.css.align : view.css && view.css.right ? 'right' : 'left'
    switch (align) {
      case 'center':
        this.ctx.translate(x, y + height / 2)
        break
      case 'right':
        this.ctx.translate(x - width / 2, y + height / 2)
        break
      default:
        this.ctx.translate(x + width / 2, y + height / 2)
        break
    }
    this.ctx.rotate(angle)
    if (!notClip && view.css && view.css.borderRadius && view.type !== 'rect') {
      this._doClip(view.css.borderRadius, width, height)
    }
    this._doShadow(view)
    if (view.id) {
      this.globalWidth[view.id] = width
      this.globalHeight[view.id] = height
    }
    return {
      width: width,
      height: height,
      x: x,
      y: y,
      extra: extra
    }
  }

  // 画文字的背景图片
  _doBackground(view) {
    this.ctx.save()
    const { width: rawWidth, height: rawHeight } = this._preProcess(view, true)

    const { background, padding } = view.css
    let pd = [0, 0, 0, 0]
    if (padding) {
      const pdg = padding.split(/\s+/)
      if (pdg.length === 1) {
        const x = pdg[0].toPx()
        pd = [x, x, x, x]
      }
      if (pdg.length === 2) {
        const x = pdg[0].toPx()
        const y = pdg[1].toPx()
        pd = [x, y, x, y]
      }
      if (pdg.length === 3) {
        const x = pdg[0].toPx()
        const y = pdg[1].toPx()
        const z = pdg[2].toPx()
        pd = [x, y, z, y]
      }
      if (pdg.length === 4) {
        const x = pdg[0].toPx()
        const y = pdg[1].toPx()
        const z = pdg[2].toPx()
        const a = pdg[3].toPx()
        pd = [x, y, z, a]
      }
    }
    const width = rawWidth + pd[1] + pd[3]
    const height = rawHeight + pd[0] + pd[2]
    this._doClip(view.css.borderRadius, width, height)
    if (GD.api.isGradient(background)) {
      GD.api.doGradient(background, width, height, this.ctx)
    } else {
      this.ctx.fillStyle = background
    }
    this.ctx.fillRect(-(width / 2), -(height / 2), width, height)

    this.ctx.restore()
  }
  _drawQRCode(view) {
    this.ctx.save()
    const { width, height } = this._preProcess(view)
    QR.api.draw(view.content, this.ctx, -width / 2, -height / 2, width, height, view.css.background, view.css.color)
    this.ctx.restore()
    this._doBorder(view, width, height)
  }
  _drawAbsImage(view) {
    if (!view.url) {
      return
    }
    this.ctx.save()
    const { width, height } = this._preProcess(view)
    // 图片失败
    if (typeof view.url === 'string') {
      this.ctx.fillStyle = '#ddd'
      this.ctx.fillRect(-(width / 2), -(height / 2), width, height)
      this.ctx.restore()
      return
    }
    // 获得缩放到图片大小级别的裁减框
    let rWidth = view.sWidth
    let rHeight = view.sHeight
    let startX = 0
    let startY = 0
    // 绘画区域比例
    const cp = width / height
    // 原图比例
    const op = view.sWidth / view.sHeight
    if (cp >= op) {
      rHeight = rWidth / cp
      startY = Math.round((view.sHeight - rHeight) / 2)
    } else {
      rWidth = rHeight * cp
      startX = Math.round((view.sWidth - rWidth) / 2)
    }
    if (view.css && view.css.mode === 'scaleToFill') {
      this.ctx.drawImage(view.url, -(width / 2), -(height / 2), width, height)
    } else {
      this.ctx.drawImage(view.url, startX, startY, rWidth, rHeight, -(width / 2), -(height / 2), width, height)
    }
    this.ctx.restore()
    this._doBorder(view, width, height)
  }

  _fillAbsText(view) {
    if (!view.text) {
      return
    }
    if (view.css.background) {
      // 生成背景
      this._doBackground(view)
    }
    this.ctx.save()
    const { width, height, extra } = this._preProcess(view, view.css.background && view.css.borderRadius)
    this.ctx.fillStyle = view.css.color || 'black'
    const { lines, lineHeight, textArray, linesArray } = extra
    // 如果设置了id，则保留 text 的长度
    if (view.id) {
      let textWidth = 0
      for (let i = 0; i < textArray.length; ++i) {
        textWidth = this.ctx.measureText(textArray[i]).width > textWidth ? this.ctx.measureText(textArray[i]).width : textWidth
      }
      this.globalWidth[view.id] = width ? (textWidth < width ? textWidth : width) : textWidth
    }
    let lineIndex = 0
    for (let j = 0; j < textArray.length; ++j) {
      const preLineLength = Math.round(textArray[j].length / linesArray[j])
      let start = 0
      let alreadyCount = 0
      for (let i = 0; i < linesArray[j]; ++i) {
        // 绘制行数大于最大行数，则直接跳出循环
        if (lineIndex >= lines) {
          break
        }
        alreadyCount = preLineLength
        let text = textArray[j].substr(start, alreadyCount)
        let measuredWith = this.ctx.measureText(text).width
        // 如果测量大小小于width一个字符的大小，则进行补齐，如果测量大小超出 width，则进行减除
        // 如果已经到文本末尾，也不要进行该循环
        while (start + alreadyCount <= textArray[j].length && (width - measuredWith > view.css.fontSize.toPx() || measuredWith > width)) {
          if (measuredWith < width) {
            text = textArray[j].substr(start, ++alreadyCount)
          } else {
            if (text.length <= 1) {
              // 如果只有一个字符时，直接跳出循环
              break
            }
            text = textArray[j].substr(start, --alreadyCount)
          }
          measuredWith = this.ctx.measureText(text).width
        }
        start += text.length
        // 如果是最后一行了，发现还有未绘制完的内容，则加...
        if (lineIndex === lines - 1 && (j < textArray.length - 1 || start < textArray[j].length)) {
          while (this.ctx.measureText(`${text}...`).width > width) {
            if (text.length <= 1) {
              // 如果只有一个字符时，直接跳出循环
              break
            }
            text = text.substring(0, text.length - 1)
          }
          text += '...'
          measuredWith = this.ctx.measureText(text).width
        }
        this.ctx.textAlign = view.css.textAlign ? view.css.textAlign : 'left'
        let x
        switch (view.css.textAlign) {
          case 'center':
            x = 0
            break
          case 'right':
            x = width / 2
            break
          default:
            x = -(width / 2)
            break
        }
        const y = -(height / 2) + (lineIndex === 0 ? view.css.fontSize.toPx() : view.css.fontSize.toPx() + lineIndex * lineHeight)
        lineIndex++
        if (view.css.textStyle === 'stroke') {
          this.ctx.strokeText(text, x, y, measuredWith)
        } else {
          this.ctx.fillText(text, x, y, measuredWith)
        }
        const fontSize = view.css.fontSize.toPx()
        if (view.css.textDecoration) {
          this.ctx.beginPath()
          if (/\bunderline\b/.test(view.css.textDecoration)) {
            this.ctx.moveTo(x, y)
            this.ctx.lineTo(x + measuredWith, y)
          }
          if (/\boverline\b/.test(view.css.textDecoration)) {
            this.ctx.moveTo(x, y - fontSize)
            this.ctx.lineTo(x + measuredWith, y - fontSize)
          }
          if (/\bline-through\b/.test(view.css.textDecoration)) {
            this.ctx.moveTo(x, y - fontSize / 3)
            this.ctx.lineTo(x + measuredWith, y - fontSize / 3)
          }
          this.ctx.closePath()
          this.ctx.strokeStyle = view.css.color
          this.ctx.stroke()
        }
      }
    }
    this.ctx.restore()
    this._doBorder(view, width, height)
  }
  _drawAbsRect(view) {
    this.ctx.save()
    const { width, height } = this._preProcess(view)
    if (GD.api.isGradient(view.css.color)) {
      GD.api.doGradient(view.css.color, width, height, this.ctx)
    } else {
      this.ctx.fillStyle = view.css.color
    }
    const borderRadius = view.css.borderRadius
    const r = borderRadius ? Math.min(borderRadius.toPx(), width / 2, height / 2) : 0
    this.ctx.beginPath()
    this.ctx.arc(-width / 2 + r, -height / 2 + r, r, 1 * Math.PI, 1.5 * Math.PI) //左上角圆弧
    this.ctx.lineTo(width / 2 - r, -height / 2)
    this.ctx.arc(width / 2 - r, -height / 2 + r, r, 1.5 * Math.PI, 2 * Math.PI) // 右上角圆弧
    this.ctx.lineTo(width / 2, height / 2 - r)
    this.ctx.arc(width / 2 - r, height / 2 - r, r, 0, 0.5 * Math.PI) // 右下角圆弧
    this.ctx.lineTo(-width / 2 + r, height / 2)
    this.ctx.arc(-width / 2 + r, height / 2 - r, r, 0.5 * Math.PI, 1 * Math.PI) // 左下角圆弧
    this.ctx.closePath()
    this.ctx.fill()
    this.ctx.restore()
    this._doBorder(view, width, height)
  }
  // shadow 支持 (x, y, blur, color), 不支持 spread
  // shadow:0px 0px 10px rgba(0,0,0,0.1);
  _doShadow(view) {
    if (!view.css || !view.css.shadow) {
      return
    }
    const box = view.css.shadow.replace(/,\s+/g, ',').split(' ')
    if (box.length > 4) {
      console.error("shadow don't spread option")
      return
    }
    this.ctx.shadowOffsetX = parseInt(box[0], 10)
    this.ctx.shadowOffsetY = parseInt(box[1], 10)
    this.ctx.shadowBlur = parseInt(box[2], 10)
    this.ctx.shadowColor = box[3]
  }
  _getAngle(angle) {
    return (Number(angle) * Math.PI) / 180
  }
}
